Traditionally, design limitations hinder the performance of an internal combustion engine. In particular, low power density and asymmetric engine geometry are major drawbacks that prevent traditional engine designs from reaching higher engine efficiency. To achieve a better engine geometry, manufacturers have designed various V-shaped engines, which position its pistons at an acute angle. Manufactures have even designed a boxer engine, which positions its pistons at 180 degrees from each other, in order to achieve a better engine geometry. To achieve a larger power density, manufacturers such as EcoMotors are currently experimenting with an opposed piston opposed cylinder engine (OPOC) engine. The design limitations of the V-shaped engine and the boxer engine are that they only allow for one crankshaft in their engine design, which prevents opposing pistons from being aligned in a straight line. Thus, an engine design with one crankshaft produces an asymmetric, unbalanced configuration of pistons. In addition to having only one crankshaft, the design limitations of the OPOC engine include long connecting rods and complicated piston configurations. The present invention is a horizontally opposed center fired engine that has almost perfect engine geometry and increases power density, engine RPM, and possibly supports variable compression ratio. The present invention utilizes many existing engine parts with little to no modifications so that manufactures do not need to design new engine parts to assemble the present invention.